A Program Project requesting support for the continuation of the polyvalent approach which has characterized the concepts and pragmatic approach by this group over the last 10 years, regarding the neuroendocrinology of reproduction and growth. Having accomplished the isolation, characterization and synthesis of thyrotropin releasing factor, luteinizing hormone releasing factor and somatostatin, all peptides of hypothalamic origin and all biologically active in man, it is proposed in this Program Project application to utilize this knowledge in fundamental studies dealing with: 1) induction of fertility as well as fertility control; 2) characterizing the hypothalamic mediators of the secretion of growth hormone, its synthetic replicates to be made available for clinical studies and treatment of growth hormone deficiences; 3) characterizing the controllers of the secretion of prolactin and similarly make their synthetic replicates available for clinical studies; 4) hypothalamic control of secretions of newly discovered growth factors of pituitary origin (ovarian growth factor, fibroblast growth factor); 5) non-hypothalamic central nervous system factors involved in various endocrine functions.